crater
crater is a free Sega Game Gear emulator written in C, with a Z80 assembler and disassembler.
What crater is
crater is a free Sega Game Gear emulator written in C, with a Z80 assembler and disassembler. It can load ROMs from its roms directory or from a path given on the command line. Display options include fullscreen, integer scaling in a window, and forcing square pixels. Keyboard and joystick or controller input are supported, with controller mappings defined through SDL mappings and a gamecontrollerdb.txt file. For compatible games, crater saves cartridge RAM to a .sav file; users can set a custom save location or turn saving off. Its assembler converts Z80 source into a Game Gear ROM image and is described as complete. The disassembler attempts to convert ROM images into assembly but cannot distinguish code from data, limiting its usefulness. Most games are described as playable with minor bugs, but the emulator lacks audio, some uncommon CPU instructions, and advanced graphics features. Save states and custom keyboard mappings are not supported. Building requires a modern C11 compiler and SDL 2; the project says OS X and Linux are tested.
Good
- Free and distributed under the MIT License
- Includes a Z80 assembler and disassembler
- Supports fullscreen and integer window scaling
- Saves cartridge RAM for compatible games
- Accepts keyboard and joystick or controller input
Watch out
- No audio support
- Save states are not supported
- Custom keyboard mappings are unavailable
- Disassembler cannot distinguish code from data
Who it suits
crater may suit Game Gear players and programmers interested in a free emulator with Z80 assembly tools. It is aimed in part at people treating emulator development as a learning project.
Verdict
crater combines Game Gear emulation with Z80 assembly tools, but it has notable compatibility and convenience gaps. Check its missing audio and save states against your needs before building it.
Plans and prices
From crater's own pricing page, checked 7 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | MIT-licensed software · requires a C11 compiler and SDL 2 |
The facts
Each one read from crater's own pages, with the date it was checked.
What it does
- Assembler
- The assembler converts Z80 assembly source into a Game Gear ROM image, and the project describes it as complete.checked 7 Oct 2026
- Assembler and disassembler
- The built-in tools convert Z80 assembly to ROM images and attempt to disassemble ROM images into assembly.checked 7 Oct 2026
- Build requirements
- Building crater requires a modern C11 compiler and SDL 2; the project says only OS X and Linux are tested.checked 7 Oct 2026
- Disassembler
- The disassembler works but cannot distinguish code from data, which the project says limits its usefulness.checked 7 Oct 2026
- Disassembler limitation
- The disassembler cannot yet distinguish code from data, which the project says limits its usefulness.checked 7 Oct 2026
- Display options
- Crater supports fullscreen mode, integer scaling in windowed mode, and an option to force square pixels.checked 7 Oct 2026
- Distribution
- The GitHub releases page states that there are no releases, and the README describes building the program with make.checked 7 Oct 2026
- Emulation status
- The emulator is almost fully functional, and most games are playable with minor bugs.checked 7 Oct 2026
- Input
- Crater supports keyboard and joystick/controller input, but custom keyboard mappings are not yet supported.checked 7 Oct 2026
- Intended audience
- The maker describes writing an emulator as a fun learning project.checked 7 Oct 2026
- Known gaps
- The emulator lacks audio support, a few uncommon CPU instructions, and some advanced graphics features.checked 7 Oct 2026
- License
- Crater is distributed under the MIT License, which permits free use, copying, modification, distribution, sublicensing, and sale subject to its conditions.checked 7 Oct 2026
- Project status
- The emulator lacks audio support, some uncommon CPU instructions, and advanced graphics features, while most games are described as playable with minor bugs.checked 7 Oct 2026
- Purpose
- Crater is a Sega Game Gear emulator with an included Z80 assembler and disassembler, written in C.checked 7 Oct 2026
- Run games
- Crater can load ROMs from its roms directory or from a path supplied on the command line.checked 7 Oct 2026
- Save data
- For games that support it, crater saves cartridge RAM to a .sav file and supports custom save locations or disabling saves.checked 7 Oct 2026
- Save states
- Save states are not yet supported.checked 7 Oct 2026
- Save support
- For compatible games, crater saves cartridge RAM to a .sav file; save states are not yet supported.checked 7 Oct 2026
Where it runs
- Controller mappings
- Crater uses SDL controller mappings and lets users define mappings in a gamecontrollerdb.txt file.checked 7 Oct 2026
- Platforms
- The project says only OS X and Linux have been tested.checked 7 Oct 2026
The company
- Maker
- GitHub identifies the repository owner as Ben Kurtovic and lists New York City as his location.checked 7 Oct 2026
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